The Scientific Core is responsible for handling the overall aspects of tissue preparation and distribution once monkeys have completed the behavioral studies as well as conducting the final MRI scans on all subjects and preparing and archiving DMA samples. The specific aims of this core are as follows: 1) To conduct MRI scans on all monkeys before perfusion to enable quantitative analyses of the brain using T1 and T2 anatomical scans, Diffusion Tensor MRI, Magnetization Transfer and MR Spectroscopy. 2) To collect and store serum, whole blood for genomic DMA and CSF samples and to measure blood pressure and electrocardiograms. 3) To conduct all perfusions of monkeys, distribute tissue samples to the Projects and cut serial whole hemisphere sections from one hemisphere of each of the subjects. Two whole hemisphere series will be stained and all other series will be saved for study by the Projects. 4) To arrange for postmortem necropsies on all subjects and send the results to the Animal Records Review Committee of the Animal core which will ensure that there are no occult diseases that could confound our observations on the relationship of age-related changes in the brain to changes in cognitive function. 5) To maintain the Active Status Database tracking all monkeys in the Program as well as all tissue samples, blood chemistries and necropsy data. In addition samples for the Projects will be blind coded to prevent experimenter bias.